This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The overall goal of this application is to develop novel methods for producing transgenic animals that can also be applied in gene therapy. Traditional methods of genetic engineering and transgenesis insert genes at random locations within the large genome of higher organisms, resulting in loss of efficiency, unpredictable results and unintended genetic consequences. Most current methods of transgenesis rely on the repair mechanisms of the zygote nucleus for the insertion of a transgene (tg) and have relatively low efficiency. We are developing what we term "Active Transgenesis" methods in which transposases, enzymes that insert DNA into the cell's chromosomes, are injected into the oocyte to increase the efficiency of transgene integration into the genome. We have recently described a method to do this in which the gene for the transposase is injected with the gene that will be inserted into the mouse genome. The oocyte then makes the transposase, and the transposase inserts the gene into the oocyte's chromosomes. In this project, we will test how useful this method is, and whether it can also be used to take out genes from mice, not only to add them. Finally, we will test whether this new method of active transgenesis can be used for gene therapy for the treatment of human disease. This project, therefore, has significance for both the generation of novel genetically engineered mice for the study of human disease, and for the treatment of human disease.